SPONTANEOUS OTOACOUSTIC EMISSIONS IN THE BOBTAIL LIZARD .3. TEMPERATURE EFFECTS

Spontaneous otoacoustic emissions (SOAE) in the ear canal of the Austr alian bobtail lizard are temperature sensitive. They shift their frequ ency up with an increase in temperature, an effect that is fully rever sible. The degree of shift is dependent not only on the center frequen cy of the SOAE (lower-frequency SOAE show a smaller shift) but also on the temperature range in question. Rates of change of frequency are 0 .014 to 0.04 oct/degrees C at 30 degrees C, and twice that at 22 degre es C. There was no strong and consistent effect of temperature on SOAE amplitudes. The above findings are very similar to those on the effec t of temperature on SOAE of frogs and mammals. Suppression tuning curv es of SOAE shifted with temperature, the largest effects being near th e center frequency in the tuning-curve's tip region.